Signatures of a degenerate many-body state of interlayer excitons in a van der Waals heterostack

Lukas Sigl, Florian Sigger, Fabian Kronowetter, Jonas Kiemle, Julian Klein, Kenji Watanabe, Takashi Taniguchi, Jonathan J. Finley, Ursula Wurstbauer, Alexander W. Holleitner

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42 Scopus citations

Abstract

Atomistic van der Waals heterostacks are ideal systems for high-temperature exciton condensation because of large exciton binding energies and long lifetimes. Charge transport and electron energy-loss spectroscopy showed first evidence of excitonic many-body states in such two-dimensional materials. Pure optical studies, the most obvious way to access the phase diagram of photogenerated excitons, have been elusive. We observe several criticalities in photogenerated exciton ensembles hosted in MoSe2-WSe2 heterostacks with respect to photoluminescence intensity, linewidth, and temporal coherence pointing towards the transition to a coherent many-body quantum state, consistent with the predicted critical degeneracy temperature. For this state, the estimated occupation is approximately 100% and the phenomena survive above 10 K.

Original languageEnglish
Article number042044
JournalPhysical Review Research
Volume2
Issue number4
DOIs
StatePublished - 22 Dec 2020

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